Synchronism-indicator.



Patented July 24, 1917.

3 SHEETSSHEET l.

G. J. VAN SWAAY & H. I. KEUS.

SYNCHRONISM INDICATOR.

APPLICATION FILED MAR. 16. 1915.

L84,58% Patented July 24,1917.

3 SHEETS-SHEET 2.

G. 1. VAN SWAAY & H. I. KEUS, SYNCHRNISM INDICATOR. APPLICATION mzo MAR. 1e, 1915.

Patented July 24, 1917.

3 SHEETS-SHEET 3.

.swrwmrro /2 ilhliT S'E% PTENT FlE GERABDUS JACOBUS VA1\T SWAAY, OF DELFT, AND HENRI ISAC KEUS, OF HENGELO, NETHERLANDS.

SYNCI-IRONISM-INDICATOR.

Applcation fi1ed March 16, 1915.

T0 all 10 wm z'z may concern.

Be it lmown that we, GERARDUS JACOBUS VAN SWAAY, residing at Delft, Holland, and HENRI Isao Knns, residing at Hengelo, Holland, subjects of the Queen of the Neth erlands, have invented certain new and use- 'ul Improvements in and Relating to Synchronisnrndicators, of which the follovvng is a specification.

This invention relates to a synchronism indicator adaptecl to indicate automatically the moment in which two machines may loe connected in parallel to the Same netvvork, the construction of this indicator being such that at the moment the required equality in frequency, phase and voltage loetween the machines occurs the machines are connected in parallel either automatically by the indicator closing a relay-circuit of the main switches or by hand. The regulation of the speed of the machines and if necessary also of the voltage to obtain the reqnired equality is eiec-ted by hand.

Of the three factors, frequency, phase and voltage, the last mentioned one is less important than the others, hecause With not exactly equal voltages lont equality in frequency and phase only wattless cnrrents arise. It is moreover not to be eared that the voltages become nnequal, as in most central stations the voltage is regulated automatically. A small difierence between the voltages of both machines cannot prevent or unfavorably aflect the connecting in parallel. The synchronism indicator according to the present invention comprises a Well known movahle element, such as a disk, snb jected to the action of magnetic ields. The invention substantially consists in the provision in such indicator of tWo electromagnets, one of which is energized by the current of one machine 01' of the network, and the other by the current of the machine to be connected in parallel, in such a manner that said currents excite fields in said magnets having a phase displacement with respoot to each other, said electrom agnets loeing further arranged with relat1on to the movable element so as te subject said element to a swinging movement as long as the irequencies of said currents difier, lont to cause said movable element to come to rest on equality in frequeney and phase coinci- Specficaton of Letters latent.

Patented July 2st, 1917.

Sera1 1\T0 14,798.

dence being attained in a position dependent on the relaton of the voltages te be connected in parallel.

Another important feature over the Well known apparatus is presented hy the fact that by a simple operation the machines can be so connected to the apparatus that the voltages of each of the machines individually are indicated or the voltages of both machines can he compared.

The apparatus according to the invention may i"nrther be so constructed that in case during the synchronizing period the voltage of the machines te be connected in parallel rises above the required voltage a maximum cutout arranged in the relay circuit of the main switches comes into action preventing these switches being closed antomatically.

The invention is further described With refercnce to the accompanying drawings, ot Which:

Figure 1 is a vertical cross section through the middle of the apparatus.

Fig. 2 is a front view of the apparatus.

Fig. 3 shows a complete diagram of. eennections including a maximum cut out device introduced in the relay circuit of the main switches.

An insulating supporting plate 1 carries the magnets 2 and supplied wvith alternat ing current. s shown in Fig. 3 said magnets are electrically connected to switch blades 4, 5 and 0, IGSPGCVGlY.

The magnets are preterably provided with two ma gnetic circuits one of Which indicated by 32 is provided with an air-gap and arranged in parallel to the ether or closed magnetic circuit the latter being highly saturated at normal impressed voltage, While the former is unsatnrated under the same conditions. Alterations in the voltage therefore cause disproportional variations in the air-gap magnetic field, so that the aluminum disk 11 rotatahle on the axis 19 and arranged in the air-gap is subjected to the action o a disproportional field- Such magnets ronder the apparatus much more eflicient than the magnets With a single magnetic circuit.

When the apparatus is out of service the disk 11 is kept in the mi ddle position lo v two oppositely Wonnd spi1al springs 13 and 14 each connected with one extremit v to a fixed post and with the other eiatremity to the axis 12. It should be understood that as Will be explained 'arther on the dis k needs only be subjected to the action of a spring or the like in one direction and in the other direction it may beat against a stop or other arresting device. By means of a pinion 16 the movements of the aXis 12 are transmitted to a toothed segment 17, a pointer 19 and their axis 18. Behind this pointer the dial plate 20 is situated. This plate is provided with a volt scale and carries the ad justable element 21 and, if desired, the synchronizng contacts 22 one of Which may be electrically connected to the pointer 19, while the other contact is insulated from the pointer and the circuit is not closed before the pointer 19 touches this contact upon the maximum force acting en the disk 11. The contacts may also both be insulated :trom the pointer and so arranged that the pointer acts as a bridging contact.

In positions 11 and IV of the switch blades l 5 and 6, 7 respectively the line voltage of the netwerk N is connected to the coil 8 and the phase-voltage of the machine M to the coil 9. Vhen the two machines are running exactly in synchronism and the ierence between the two requencies is. The

greater the deilection of the pointer the smaller is also the dilierence in frequency; in other Words the numher of oscillations within a certain period of time is a measure for the inequality of the 'reque'ncies.

During synchronizing the maximum torque can only arise in two cases provided that the switch blades are in positions II and IV, namely:

a. VVhen the disk 11 is subjected to the action of fields excited by voltages having a phase diflerence of exactly 90; in other words When between the corresponding voltages of the machine and the network or of the machines phase-coincidence occurs.

Z). When the disk 11 is subjected to the action of magnetic fields excited by voltages having a phase diilerence of exactly 270 or in ether Words, when between the corresponding voltages of the machine and the network 01 of the machines a phase difference of 180 exists.

Only in the extreme position of the pointer in case a it is allowed to connect in parallel. The extreme position in case b, being opposite in relation to the middle position to the side where the element 21 is placed, has no ellect. It is olwious that the pointer needs not deliect to this side and may be arrested by a stop instead of a spring.

The three conditions Which should be satislied before the main switches may be thrown in are only satisfied for a short periocl. At a difierence in requency of 0.1 per cent. and 50 cycles the movement of the pointer is reversed after 10 seconds during Which period it remains in the eX- treme position mentioned under cc, keeping the relay-circuit of the main switehes closed. This period sufiices to allow the relays to close the main switches, or to efiect the throwing in of the main switch by hand if the apparatus is not provided With contacts 22.

lhe connecting in parallel is efiected in the lolloWing manner:

The switches 1, 5 and 0,7 are iirst placed in positions 11 and II respectively, so that the magnet coils 8, 9 are conneoted to the line and phase-voltages respectively of the net N. hereupon the voltage (provided the Same is not automatically kept constant) is regulated in such a way that the pointer 19 assumes a position above the adjustable element 21. H for one reason or the-other it is not desirable to regulate the voltage then the element 21 is placed under the pointer 19. Hereupon the switches 4, 5 and 6, 7 are thrown over into the positions 1 and IV respectively and the voltageof the machine M is regulated in such a 1nanner that the pointer 19 again comes to rest over the element 21. The apparatus hereb} acts as a voltmeter for the machine M.

The two voltages now being equal the suitches are placed in positions 11 and IV respectively. As a rule the disk 11 will begin to swing. 1f the numl er of oscillations increases With the speed o the machine this indicates that the machine to be switched in parallel runs too ast. When regulating the speed of the machine in the Wrong direction the deflection of the pointer diminishes. By correspondingly altering the speed of the machine in the opposite direction the clefiection of the pointer is increased until the latter assumes a position above the element 21. At this moment the machine may be connected in parallel manually or automati cally. The apparatus thereiore indicates, uhether the speed of the machine to be switched in parallel is regulated in the right or in the wrong direction.

In the circuit of the contacts 22 the device shown at the top of Fig. 3 may be included.

This device is adapted to prevent connecting in parallel, in case the voltage ofthe net or 0 the machine rises during the synehronizing period. A special device 'for preventing eonnecting in parallel when the voltage drops is supefluous, because in that case the pointer does not reach the element 21.

This auxiliar device only becomes necessary under very particular circmnstances. The magnetic air-gap circuits 82 of the magnets 2 and 3 are provided witl1 secondary coils 23, 24 adapted to energize electromagnets 25, 26 of maximum cut-outs. '1he armatures 27, 28 attached to springs carry contacts normally electrically connecting the contact plate 29, the strip 30 and the contact plate 31. The contact plates 29 and 31 are connected into the relaycircuit of the main switch, so that the current of this circuit passes from the plate 29 through the contact 27, the strip 30, the contact 28 and the plate 31. If the voltage of one of the two primary coils 8, 9 rises above the maximum predetermined alue, the excess in voltage Will cause a disproportional increase in the voltage of the corresponding secondary coil 23. 24 and the corresponding magnet 25, 26 will consequently be so energized that the armature is attracted. The circuit including the contacts 22 and the contacts 29, 30 and 31 is thus opened, so that automatic switching in of the main switch is pre- Vented.

The apparatus according to the present invention possesses the following advantages:

1. Phase voltmeters are not required.

2. A zero voltmeter is super-fluous, loecause the pointer 19 does not reach the position aloove the element 21, at which the machine to be connected in parallel may he switched in, unless there is equality in voltage between the network and the machine.

3. It is perceptible vvhether the speed of the machine to be connected in parallel must he increased or decreased during the synchronizing period.

4. Betere connecting in parallel the voltages may be controlled readily and in a simple marmer.

5. The apparatus alloWs 'or connecting in parallel automatically in a simple manner loy means of a contact device.

6. The apparatus is simple in construction and handling, reliable and inexpensive.

It must be understood that the phase difference in the coils 8 and 9 for producing a torque on the disk 11 may be olotained in any other suitable manner. The disk itself may be circular as shown or of segmental form or may be replaced by any other movable member suitable for the purpose. In order to damp the swinging movement of the disk a steel magnet may be provided, so that the disk moves through the magnetic field of Same.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is 1. In a synchronism indicator comprising a movalole element subjected to the action of magnetic iields, tvvo eleetromagnets one of Which is energized by the current of one machine or of the nctwork and the other by the current of the machine to be connected in parallel in such a manner that said cur rents excite fields in said magnets having a phase displacement with respect to each other, said electromagnets loeing fnrthcr airanged with relation to the movable element so as to subject said element to a swinging movement as long as the frequencies ditter, lont to cause said m0 able element to come to rest on equality in 'requency and phase coincidence being attained in a position clependent on the relation of the voltages of the two sources to be connected in parallel, and a yielding member produeing a resisting force acting upon said movahle element increasing with the distance of said element trom its normal position.

2. In a synchronism indicator comprising a movable element subjected to the action of magnetic fields, tWo electromagnets connected to the machines or to the machine and the networks to be connected in parallel and a cting upon the movable element so as to subject said element to a swinging movement as long as the frequencies in the machines or in the machine and the netwerk te be connected in parallel differ, but to cause said movable element to adjust itself in a position dependent on the relation of the voltages of said magnets, a yielding member producing a resisting orce acting upon said movable element increasing with the distance of said element from its normal position, switching means for connecting both magnetizing coils of said electromagnets to each of the machines or to the netwerk, a pointer connected to the movable element and a volt scale or indicating or comparing the voltages of the machines individually or of the network.

3. In a synchronism indicator comprising a movable element sulojected to the action of magnetic fields, tivo electromagnets subjecting the movable element to a swinging movement as long as the frequencies in the machines or in the machine and the net- Work difler, but causing said element to come to rest on equality in frequency and phase coincidence heing attained, a yielding member producing a resisting force acting upon said movable element and increasing with the distance of said element from its normal position, svvitching means for connecting both magnetizing coils of said electromagnets to each of the machines or to the network, a pointer connected t0 said movable element, a volt scale, an element adjustable on said volt scale to indicate the angle of defiection of said pointer at the moment the required equality in frequency, phase and voltage is obtained.

4. In a synchronism indicator compris ing a movalole element sulojected to the actien of magnetic fields, two electromagnets i subjecting the movalole element to a swinging movement as long as the frequencies in the machines or in the machine and the network difi'er, but causing said element to come to rest on equality in frequency and phase coincidence being attained, a yielding member producin a resisting orce acting upon said movab e element and increasing with the distance of said element from its normal position, switching means or connecting both magnetizing coils of said elec tromagnets to each of the machines or to the network, a pointer connected t0 said movable element, a volt scale, an element adjustable on said volt scale, contacts on said ad justable element, said contacts being closed automatically by the pointer on the required equality in frequency, ohase and voltage being obtained.

5. In a synchronism indicator comprising a movableclement subjected to the action of magnetic fields, two electromagnets, one of Which is energized by the current of one machine or of the network and the other by the current of the machine to be connected in parallel in such a manner that said currents excite fields in said magnets having a phase displacement with respect to each other, said electromagnets being further arranged with relation to the movable element so as to subject said element to a swinging movement as long as the frequencies difler, but to cause said movable element to come to rest on equality in frequency and phase coincidence being attained, in a postion dependent on the relation of the voltages of the two sources to be connected in parallel, said magnets havng two magnetic circuits, one of Which is closed and highly saturated under normal working conditions and the other is provided with an air gap and unsaturated, the closed circuit receiving the magnetizing coils and the magnetic field in said air gap circuit acting upon said movable element.

6. In a synchronism indicator comprising a movable element, subjected to the action of magnetic fields, two electromztgnets subjecting the movable element to a swinging movement as long as the requencies in the machines or in the machine and the network diiier, lont causing said element to come to rest on equality in frequency and phase coincidence being attained, a yielding member producing a resisting force acting upon said movable element and increasing With the distance of said element from its normal position, adjustable contacts to be closed automatically by the movable element on the required equality in frequency, phase and voltage being obtained, lines leading from said contacts and an automatic circuit breaking device in said lines, breaking same on the voltage of one of the machines or of both machines rising above a predetermincd value.

7. In a synchronism indicator comprising a movable element subjected to the action of magnetic fields, two electromagnets subjecting the movable element to a swinging movement as long as the frequencies in the machines or in the machine and the network diifer, but causing said element to come to rest on equality in frequency and phase coincidence being attained, said magnets having two magnetic circuits, one of which is closed and highly saturated under normal working .conditions and the other is provided With an air gap and unsaturated, the closed circuit receiving the magnetizing coils and the magnetic field in said air gap circuit actng upon said movable element, secondary coils on said air gap circuits of said electromagnets, relays energized by the current from said secondary coils, and a circuit breaker operated by said relays 011 the voltage of one of the machines or of both machines rising above a predetermined value.

In testimony Whereof we have signed our names to this specification.

GERARDUS JACOBUS vni swau. HENRI ISAC KEUS.

Gopies of this patent may be obtained for five cents each, by addressng; the Gommissoner of latents, Washington, D. 0. 

